Toyota Corolla Cross Owners & Service Manuals

Toyota Corolla Cross: Impact Detection Sensor Circuit Malfunction (B124300)

Toyota Corolla Cross (2022-2024) Service Manual / Vehicle Interior / Door Lock / Power Door Lock Control System / Impact Detection Sensor Circuit Malfunction (B124300)

DESCRIPTION

If the collision door lock release function does not operate normally, or an open or short in the GSW input circuit of the main body ECU (multiplex network body ECU) is detected, DTC B124300 will be stored.

HINT:

If DTC B124300 is stored, the automatic door lock function, and collision door lock release function will be prohibited.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B124300

Impact Detection Sensor Circuit Malfunction

A malfunction occurs in the GSW input circuit of the main body ECU (multiplex network body ECU).
  • Main body ECU (multiplex network body ECU)
  • Power distribution box assembly
  • Airbag ECU assembly
  • Wire harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

    Click here

  • If the main body ECU (multiplex network body ECU) is replaced, refer to the Registration.*
    • for HEV Model: Click here
    • for Gasoline Model: Click here
      • *: w/ Start Key System

PROCEDURE

1.

CHECK DTC OUTPUT

(a) Clear the DTCs.

Body Electrical > Main Body > Clear DTCs

(b) Recheck for DTCs.

Body Electrical > Main Body > Trouble Codes

Result

Proceed to

B124300 is not output

A

B124300 is output

B
A

USE SIMULATION METHOD TO CHECK

B

2.

CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) (GSW VOLTAGE)

CAUTION:

Wait at least 60 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

NOTICE:

Turning the ignition switch to ON with the airbag ECU assembly connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

(a) Disconnect the cable from the negative (-) auxiliary battery terminal.

(b) Disconnect the airbag ECU assembly connector.

(c) Connect the cable to the negative (-) auxiliary battery terminal.

(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

I47-25 (GSW) - Body ground

Ignition switch ON

4.3 to 5.5 V

*a

Front view of wire harness connector

(to Airbag ECU Assembly)
NG

GO TO STEP 5

OK

3.

REPLACE AIRBAG ECU ASSEMBLY

CAUTION:

Wait at least 60 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

(a) Disconnect the cable from the negative (-) auxiliary battery terminal.

(b) Replace the airbag ECU assembly.

Click here

NEXT

4.

CHECK DTC OUTPUT

(a) Clear the DTCs.

Body Electrical > Main Body > Clear DTCs

(b) Recheck for DTCs.

Body Electrical > Main Body > Trouble Codes

Result

Proceed to

B124300 is not output

A

B124300 is output

B
A

END (AIRBAG ECU ASSEMBLY WAS DEFECTIVE)
B

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

5.

CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - POWER DISTRIBUTION BOX ASSEMBLY)

CAUTION:

Wait at least 60 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

(a) Disconnect the cable from the negative (-) auxiliary battery terminal.

(b) Disconnect the 8C power distribution box assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

I47-25 (GSW) - 8C-43

Always

Below 1 Ω

I47-25 (GSW) or 8C-43 - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

6.

INSPECT POWER DISTRIBUTION BOX ASSEMBLY

(a) Remove the power distribution box assembly.

Click here

(b) Remove the main body ECU (multiplex network body ECU).

(c) Measure the resistance according to the value(s) in the table below.

*a

Component without harness connected

(Power Distribution Box Assembly)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

MB-20 (GSW) - 8C-43

Always

Below 1 Ω
OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE POWER DISTRIBUTION BOX ASSEMBLY

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